There exists a strong environmental and economic demand for accelerated activity bacteria capable of breaking down unwanted solids suspended or partially dissolved in aqueous media. Such solids have been classified in several ways including: total suspended solids (TSS), total volatile solids (TVS), sludge, and collectively, fats, oils and greases (FOG). Such solids have also been classified in their ability to enhance the life-bearing capabilities of the liquid in which they are suspended. Normal classifications include chemical oxygen demand (COD) and biological oxygen demand (BOD). Accelerated activity bacteria (i.e. highly active bacteria) have also been used to breakdown certain toxic wastes such as phenolic compounds and chromium by-products.
In a typical application, active bacteria, after acclimation, are used to treat toxic wastes to produce harmless, easily disposed non-toxic end products. Highly active bacteria have also been used to control or eliminate malodorous aqueous effluents. Malodorous substances such as hydrogen sulfide, ammonia or butyric acid, if broken down or denatured, are essentially odorless. An example of a material which falls in both the classifications of toxic material and malodorous material is hydrogen sulfide which, in its gaseous form or an aqueous solution is both toxic and malodorous.
Several strains of bacteria, normally found in soil, have been found to significantly shorten the breakdown cycle of solid wastes generally found in sewage. Examples of such soil bacteria include the genera of Arthrobacter, Bacillus, Pseudomonas, Flavobacterium and Acinetobacter, to mention a few. Certain bacteria found in animal intestines have been found to produce enzymes which, in turn, preferrably breakdown fats, oils and greases. Examples of such enzymes are found in many ruminant animals. Especially of note are the lipase producers found in sheep. Lastly, bacteria including varieties of Rhodospirillum and Chromatium are commonly found in salt water and have been found to rapidly and efficiently breakdown aqueous solutions of hydrogen sulfide. These are but a few examples of the many circumstances in which bacteria found in one environment can be usefully employed to remove unwanted species and solutes in other environments.
The problem of identifying bacteria from one environment useful to remove an unwanted species from another environment has been exacerbated by difficulties in isolating the bacteria, culturing them, transporting them to the new site for application and maintaining their activity while stored on-site. The use of water as a transporting agent (from manufacturer to plant) has the problem of limited bacterial counts and short shelf life of the bacteria. Two other techniques presently used for preserving the activity of bacteria include mixing the bacteria with bran media and freeze-drying (lyophilizing). Mixing bacteria with bran has the unfortunate drawback of dramatically increasing the time between dispensing the bran/bacterial medium into the effluent stream to be treated and full activity of the bacteria. In instances where bacteria need to be acclimated, e.g., where toxic wastes are to be treated, further time for acclimation is required. Futhermore, the bran itself creates sludge.
Freeze-drying of bacterial product to enhance its shelf life has the unfortunate drawbacks of the increased cost associated therewith. Also, freeze-dried bacteria need to be rehydrated prior to achieving optimal activity.
The net effect of these problems and issues is that even with the substantial ecological advantage of the use of bacterial cultures to treat unwanted materials in, for example, waste water, economic considerations have limited their utilization. This is not to say that no efforts have been made to culture specific bacterial products on-site at waste water treatment plants. The systems used in these "on-site" applications have typically been easily disturbed and were capable of producing only limited amounts of the desired bacteria for the space required.
Such systems only provide food and light (when necessary), and they are under the control of the bacterial manufacturer. The intent is to allow the purchaser the ability to culture its own specialized strains of bacteria, blended and acclimated especially for the given environment. The systems are designed for use on solids and liquids including applications such as toxic waste sites, industrial plants, and air scrubber systems as a replacement to chemicals such as potassium permanganite and sodium hydroxide.
Surface area may be provided within a plant, but not for the purpose of selective bacterial culturing. These systems are designed to allow the waste to come in contact with the flow of solids. The systems include a trickling filter and rotating biological disks. They are not attempting to culture high quality bacteria, but are capturing whatever bacteria exists within a given flow. These bacteria are subject to upsets due to changes in the liquid, including pH variations, temperature changes and chemicals present. Upsets take from four to ten days, sometimes longer, to recover without the addition of a highly concentrated bacterial solution. With this solution, recovery can be as rapid as four hours, and will typically be complete within twelve hours.
The system-cultured bacteria are within a given basin that uses a highly controlled environment to optimize the growth of a given culture on the existing location, to optimize the treatment of sewage, to reduce or concentrate hazardous waste, to act within an air scrubber to break down the collected chemicals within the system, to break down fats, oils, and greases, and to reduce the volume of sludge in waste water.
It is known that various bacterial systems containing separate species of bacteria tend to symbiotically reduce complex masses of unwanted materials to harmless gases, water, and simple harmless substances. Such symbiotic bacterial reductions are more successful if large reproductive surface areas are provided.
This "on-site" or remote site bacterial culturing system overcomes the above problems experienced by prior art systems. Moreover this system permits waste water plant operators to determine precisely which microbes are to be cultured, the order of culturing, and the volume of bacteria to be produced. This mitigates the problems of time, transportation and expense (along with loss of activity) discussed above. This also permits waste water plant operators to produce precisely cultured bacterial media on an "as needed" basis. In this manner, costs can be reduced and ecological concerns can be more adequately addressed.